Beginner Exercise 21 / Solution

Sub-page of BeginnerExercise21


White escapes!  

Black is caught in a connect-and-die. If Black a, White b captures. Otherwise, White captures at a, and is connected to the outside and escapes, thus living (by tsumego convention). White can also live by starting at a.

zinger: White a does not work - see the diagrams below.

White failure  

The double atari is wrong here: Black chooses which group to sacrifice, preventing White from connecting and escaping. Note the the bottom row of four is good for at most one eye. After White captures (perforce: if White tries to start making an eye below, Black will capture and White only gets one eye), Black reduces that to no eyes with two hanes:

White failure (cont'd)  

This shows that White has only the one eye.

White failure (cont'd)  

Wauske: If white were to play 5 wouldn't it mean that, if used correctly, it would live? Meaning that black can respond at a or b white would respond at the other and that c would be followed up by d?

White failure (cont'd)  

unkx80: Are you saying that B6 may be answered by W7? Then B8 can capture the W7 stone.

(Note: B8 is not neccessary.)

White failure (cont'd)  

This is the end result. Is White alive, i.e. does White have two eyes?

Dennis Heldens:


I'm a beginner, but I think that if black plays B2, a or tenuki, white should play W3. Black is then caught in a snapback, wich makes life for white without need for connecting to the outside. So best for black is to play B2 at W3 to prevent that. Correct?

Andrew Grant: No. Once White plays W1 she is alive, since the two black stones cannot escape. If Black plays B2 White should ignore it and play elsewhere since White is alive already. W3 only captures another two stones, which is too small to bother about except in the late endgame. And if Black plays B2 at W3 it's just a waste of a ko threat.

See also:

Beginner Exercise 21 / Solution last edited by on January 26, 2008 - 21:03
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